Architecture of three-dimensional memory device and methods regarding the same

ABSTRACT

Architectures of 3D memory arrays, systems, and methods regarding the same are described. An array may include a substrate arranged with conductive contacts in a geometric pattern and openings through alternative layers of conductive and insulative material that may decrease the spacing between the openings while maintaining a dielectric thickness to sustain the voltage to be applied to the array. After etching material, a sacrificial layer may be deposited in a trench that forms a serpentine shape. Portions of the sacrificial layer may be removed to form openings, into which cell material is deposited. An insulative material may be formed in contact with the sacrificial layer. The conductive pillars extend substantially perpendicular to the planes of the conductive material and the substrate, and couple to conductive contacts. A chalcogenide material may be formed in the recesses partially around the conductive pillars.

BACKGROUND

The following relates generally to a system that includes at least onememory device and more specifically to the architecture ofthree-dimensional memory devices and methods regarding the same.

Memory devices are widely used to store information in variouselectronic devices such as computers, wireless communication devices,cameras, digital displays, and the like. Information is stored byprogramming different states of a memory device. For example, binarydevices most often store one of two states, often denoted by a logic 1or a logic 0. In other devices, more than two states may be stored. Toaccess the stored information, a component of the device may read, orsense, at least one stored state in the memory device. To storeinformation, a component of the device may write, or program, the statein the memory device.

Various types of memory devices exist, including magnetic hard disks,random access memory (RAM), read only memory (ROM), dynamic RAM (DRAM),synchronous dynamic RAM (SDRAM), ferroelectric RAM (FeRAM), magnetic RAM(MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM),other chalcogenide-based memories, and others. Memory devices may bevolatile or non-volatile.

Improving memory devices, generally, may include increasing memory celldensity, increasing read/write speeds, increasing reliability,increasing data retention, reducing power consumption, or reducingmanufacturing costs, among other metrics. Solutions for saving space inthe memory array, increasing the memory cell density, or decreasingoverall power usage of the memory array with three-dimensional verticalarchitecture may be desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a three-dimensional (3D) memory arraythat supports architecture of three-dimensional memory device andmethods regarding the same in accordance with examples as disclosedherein.

FIG. 2A illustrates a bottom view of an example 3D memory array inaccordance with examples as disclosed herein.

FIG. 2B illustrates a side view of an example 3D memory array inaccordance with examples as disclosed herein.

FIGS. 3A through 3E illustrate various views of example 3D memory arraysin accordance with examples as disclosed herein.

FIGS. 4A through 4E illustrate various views of example 3D memory arraysin accordance with examples as disclosed herein.

FIGS. 5A through 5C illustrate various views of example 3D memory arraysin accordance with examples as disclosed herein.

FIGS. 6A through 6B illustrate various views of example 3D memory arraysin accordance with examples as disclosed herein.

FIGS. 7A through 7B illustrate various views of example 3D memory arraysin accordance with examples as disclosed herein.

FIGS. 8 through 11 show flowcharts illustrating a method or methods thatsupport architecture of three-dimensional memory device and methodsregarding the same in accordance with examples as disclosed herein.

DETAILED DESCRIPTION

The present disclosure relates to three-dimensional (3D) verticalself-selecting memory arrays with an increased density of memory cells,and methods of processing the same. The memory arrays may include anarrangement of conductive contacts and openings through alternativelayers of conductive materials and insulative material that may decreasethe spacing between the memory cells while maintaining a dielectricthickness to sustain the voltage to be applied to the memory array.

In some examples, a 3D memory array may include a substrate with aplurality of contacts arranged in a pattern (e.g., a geometric pattern)and a first insulative material (e.g., a dielectric material) formed onthe substrate. A plurality of planes of a conductive material may beseparated by one another by a second insulative material (e.g., adielectric material) and formed on the substrate material. The planes ofconductive material may be examples of word lines.

During manufacturing of such a memory array, a trench may be formed in ashape that separates odd and even word line (WL) planes to create “comb”structures (e.g., structures that look like a tool with fingers andspace between the fingers). The trench may any geometric configurationand include odd and even groups of fingers of the comb facing oneanother at a fixed distance. In some examples, the trench may be formedin a serpentine shape. The trench may divide each plane of conductivematerial into two sections or two plates. Each place of conductivematerial may be an example of a word line plate. In some examples,inside the trench, the planes of the conductive material may be etchedin such a way that the dielectric materials and the conductive materialsform a plurality of recesses, where each recess may be configured toreceive a storage element material (e.g., a chalcogenide material). Asacrificial layer (e.g., a conformal material) may be deposited in thetrench and, in some cases, the sacrificial layer fills the recesses. Aninsulative material may be deposited in the trench on top of thesacrificial layer. The sacrificial layer and the insulative layer mayform a serpentine shape. In some examples, other geometricconfigurations of the trench are contemplated.

Portions of the sacrificial layer and the insulative may be removed toform openings. The openings may expose portions of the substrate, theplurality of conductive contacts, and portions of the conductivematerials and dielectric materials. A storage element material (e.g.,the chalcogenide material) may be deposited in the openings. The storageelement material may fill the recesses formed by the dielectricmaterials and the conductive materials. The storage element material maybe partially removed from the openings such that only the storageelement materials in the recesses remain.

Conductive pillars may be formed in the openings that include thestorage element materials in the recesses. The conductive pillars may beexamples of a digit lines. The conductive pillars may be arranged toextend (e.g., substantially perpendicular) to the planes of theconductive material and the substrate. Each conductive pillar may becoupled with a different conductive contact. The pillars may be formedof a barrier material and a conductive material.

Such configurations of a memory array and the methods of manufacturingmay allow a higher-density of memory cells relative to previoussolutions. Each memory cell (e.g., storage element material) may berecessed inside opposite sides of the conductive pillar to ensure thecell isolation. Such a configuration may allow for a tighter control ofcell thickness and dimension with respect to some previous solutions.Each plane of conductive material that intersects the conductive pillarmay form two memory cells addressed by a first word line plate in theplane and a second word line plate in the plane. Each conductive pillarmay be decoded by a transistor positioned at the bottom or top of thememory array. The transistor may be an example of a digit line selectorformed in a regular matrix.

Features of the disclosure are initially described in the context of amemory array as described with reference to FIG. 1. Features of thedisclosure are described in the context of different views of example 3Dmemory arrays during processing steps as described with reference toFIGS. 2-7. These and other features of the disclosure are furtherillustrated by and described with reference to flowcharts that relate to3D vertical memory array architecture as described with references toFIGS. 8-11.

FIG. 1 illustrates an example of a 3D memory array 100 in accordancewith aspects of the present disclosure. Memory array 100 may include afirst array or deck 105 of memory cells that is positioned above asubstrate 104 and a second array or deck 108 of memory cells on top ofthe first array or deck 105.

Memory array 100 may include word lines 110 and digit lines 115. Memorycells of the first deck 105 and the second deck 108 each may have one ormore self-selecting memory cells. Although some elements included inFIG. 1 are labeled with a numeric indicator, other correspondingelements are not labeled, though they are the same or would beunderstood to be similar.

A stack of memory cells may include a first dielectric material 120, astorage element material 125 (e.g., chalcogenide material), a seconddielectric material 130, a storage element material 135 (e.g.,chalcogenide material), and a third dielectric material 140. Theself-selecting memory cells of the first deck 105 and second deck 108may, in some examples, have common conductive lines such thatcorresponding self-selecting memory cells of each deck 105 and 108 mayshare digit lines 115 or word lines 110.

In some examples, a memory cell may be programmed by providing anelectric pulse to the cell, which may include a memory storage element.The pulse may be provided via a first access line (e.g., word line 110)or a second access line (e.g., digit line 115), or a combinationthereof. In some cases, upon providing the pulse, ions may migratewithin the memory storage element, depending on the polarity of thememory cell. Thus, a concentration of ions relative to the first side orthe second side of the memory storage element may be based at least inpart on a polarity of a voltage between the first access line and thesecond access line. In some cases, asymmetrically shaped memory storageelements may cause ions to be more crowded at portions of an elementhaving more area. Certain portions of the memory storage element mayhave a higher resistivity and thus may give rise to a higher thresholdvoltage than other portions of the memory storage element. Thisdescription of ion migration represents an example of a mechanism of theself-selecting memory cell for achieving the results described herein.This example of a mechanism should not be considered limiting. Thisdisclosure also includes other examples of mechanisms of theself-selecting memory cell for achieving the results described herein.

The architecture of memory array 100 may be referred to as a cross-pointarchitecture, in some cases, in which a memory cell is formed at atopological cross-point between a word line 110 and a digit line 115.Such a cross-point architecture may offer relatively high-density datastorage with lower production costs compared to other memoryarchitectures. For example, the cross-point architecture may have memorycells with a reduced area and, resultantly, an increased memory celldensity compared to other architectures.

While the example of FIG. 1 shows two memory decks 105 and 108, otherconfigurations are possible. In some examples, a single memory deck ofself-selecting memory cells may be constructed above a substrate 104,which may be referred to as a two-dimensional memory. In some examples,a three or four memory decks of memory cells may be configured in asimilar manner in a three-dimensional cross point architecture.

The memory array 100 may include a substrate 104 with a plurality ofcontacts arranged in a grid or staggered pattern. In some cases, theplurality of contacts may extend through the substrate and couple withan access line of the memory array 100. The memory array 100 may includea plurality of planes of a conductive material separated by one anotherby a second insulative material formed on the first insulative materialon the substrate material. Each of the plurality of planes of theconductive material may include a plurality of recesses formed therein.The plurality of planes, for example, word line plates, may be obtainedby a replacement process by using a sacrificial layer (e.g., a conformallayer) for etching during a stack deposition processing step, removingthe conformal layer after cell definition and replacing the conformallayer with a more conductive material.

An insulative material may be formed in a serpentine shape through thesecond insulative material and the conductive material. A plurality ofconductive pillars may be arranged in openings to extend substantiallyperpendicular to the plurality of planes of the conductive material andthe substrate. Each respective one of the plurality of conductivepillars may be coupled to a different one of the conductive contacts.

In some examples, the memory decks 105 and 108 may include chalcogenidematerial configured to store logic states. For example, the memory cellsof the memory decks 105 and 108 may be examples of self-selecting memorycells. A chalcogenide material may be formed in the plurality ofrecesses such that the chalcogenide material in each respective one ofthe plurality of recesses is at least partially in contact with one ofthe plurality of conductive pillars.

FIG. 2A illustrates a bottom view of an example 3D memory array 200-a inaccordance with examples as disclosed herein. The memory array 200-a mayinclude a plurality of conductive contacts 235 formed in a substrate 104and extend through the substrate 104 and couple with an access line ofthe memory array 100. For example, the substrate 104 may be a dielectricmaterial, such as a dielectric film.

A single conductive contact of the plurality of conductive contacts 235may be configured to couple any single vertical pillar with a transistor(not shown). The plurality of conductive contacts 235 may be arranged ina grid pattern. In some examples, a respective one of the plurality ofconductive contacts 235 may be surrounded by up to eight otherconductive contacts 235. In some examples, the plurality of conductivecontacts 235 may be arranged in a staggered pattern or a hexagonalpattern. For example, a respective one of the plurality of conductivecontacts 235 may be surrounded by up to six other conductive contacts235 (see FIGS. 6A and 6B).

FIG. 2B illustrates a side view of an example 3D memory array 200-b inaccordance with examples as disclosed herein. The memory array 200-b mayinclude plurality of conductive contacts 235 may be formed in thesubstrate 104. The memory array 200-b may also include a plurality ofstacked planes of an insulative material 240 and a plurality of stackedplanes of a conductive material 245 (e.g., word lines planes or wordline plates). The stacked planes of conductive material 245 may beseparated in a z-direction (e.g., separated vertically) from one anotherby the plurality of planes of the insulative material 240. For example,a first plane (e.g., a bottom plane) of the second insulative material240 may be formed (e.g., deposited) on the plane of the substrate 104,and then a plane of the conductive material 245 may be formed on thefirst plane of the second insulative material 240. In some examples, alayer of the first insulative material 240 may be deposited on thesubstrate 104. In some examples, the conductive material 245 may be alayer of conductive carbon or other conductive layer compatible withactive materials. In some examples, the conductive material 245 mayinclude conductive layers separated by active material through aprotective barrier. The conductive material 245 may be configured tofunction as at least one word line plate. In some examples, theconductive material 245 and the insulative material 240 form a pluralityof layers, such as alternating layers.

Additional planes of the second insulative material 240 may be formed onthe conductive material 245 in an alternating manner as illustrated inFIG. 2B. The second insulative material 240 may be a dielectricmaterial, such as a dielectric film or layer. In some examples, thesecond insulative material 240 and the substrate 104 may be the sametype of insulative material. Examples of the insulative materialsdisclosed herein include, but are not limited to dielectric materials,such as silicon oxide.

Each respective one of the plurality of planes of the conductivematerial 245 may be at (e.g., form) a different level of the 3D memoryarray 200-b. Individual planes of material that form memory cells may bereferred to as a deck of the 3D memory array 200-b. The conductivematerial 245 may comprise (e.g., be formed of) a metallic (orsemi-metallic) material or a semiconductor material such as a dopedpolysilicon material, among others. In some examples, the conductivematerial 245 may be a plane of conductive carbon.

Six planes of the conductive material 245 and seven planes of the secondinsulative material 240 are shown in FIG. 2B. The seventh plane of thesecond insulative material 240 may be a topmost layer of the 3D memoryarray 200-b. The quantity of planes of the conductive material 245 andthe second insulative material 240 are not limited to the quantitiesillustrated in FIG. 2B. The conductive material 245 and the secondinsulative material 240 may be arranged into more than six decks or lessthan six decks.

FIGS. 3A-E illustrates various views of example 3D memory arrays 200-c,200-d, 200-e, and 200-f during a series of steps or processes that maybe performed to form a stacked memory device, in accordance withexamples as disclosed herein. Specifically, in FIGS. 3A-E, a process offorming even and odd word line planes is shown.

FIG. 3A illustrates a top view of an example 3D memory array 200-c,which may be an example of the memory array 200-b illustrated in FIG. 2Bafter a trench 350 is formed. FIG. 3B illustrates a cross-sectional viewof an example 3D memory array 200-d along section line A-A′ during aprocess step subsequent to what is illustrated in FIG. 3A. FIG. 3Cillustrates a cross-sectional view of an example 3D memory array 200-ealong section line A-A′ during a process step subsequent to what isillustrated in FIG. 3B. FIG. 3D illustrates a cross-sectional view of anexample 3D memory array 200-f along section line A-A′ during a processstep subsequent to what is illustrated in FIG. 3C. FIG. 3E illustrates atop view of an example 3D memory array 200-f of section line B-B′ duringa process step subsequent to what is illustrated in FIG. 3C. FIGS. 3A-Eillustrate a series of steps or processes that may be performed to forma stacked memory device.

FIG. 3A illustrates forming the trench 350 through the alternatingplanes of conductive material 245 (shown in FIG. 3B) and the secondinsulative material 240 (shown in FIG. 3B) of memory array 200-c. Thetrench 350 may expose the substrate 104 (previously shown in FIGS. 2Aand 2B) and the conductive contacts 235 (previously shown in FIGS. 2Aand 2B) at the bottom of the trench 350.

The trench 350 may be etched from top to bottom and etched in aserpentine-shape. For instance, the trench 350 may pass over a row ofthe conductive contacts 235 in a first direction (e.g., from left toright) and then pass over an adjacent row of the conductive contacts 235in a second direction that is opposite to the first direction (e.g.,from right to left). With reference to the example of FIG. 3A, thetrench 350 passes over a first row of the conductive contacts 235 fromleft to right, then “turns” and passes over the next (second) row ofconductive contacts 235 (adjacent to the first row) from right to left.The trench 350 “turns” again and passes over the next (third) row ofconductive contacts 235 (adjacent to the second row) from left to right.The trench 350 “turns” again and passes over the next (fourth) row ofconductive contacts 235 (adjacent to the third row) from right to leftand then “turns” again and passes over the next (fifth) row ofconductive contacts 235 at the bottom of FIG. 3A (adjacent to the fourthrow) from left to right.

The trench 350 may bifurcate each plane of the conductive material 245into at least two portions: a first portion 308 and a second portion309. Each portion of a plane of the conductive material 245 may be adifferent access line (e.g., even word line or odd word line) of a deck.For example, the first portion 308 may be a first access line of a deckof the 3D memory array 200-c and the second portion 309 may be a secondaccess line of the same deck of the 3D memory array 200-c. The extensionof the fingers forming the even or odd planes may be defined based onthe resistivity of an electrode used and by the level of currentdelivery requested. Specifically, the depth of the recesses is defineddepending on the thickness desired for the memory cell.

FIG. 3B illustrates forming a plurality of recesses 315 in theconductive material 245 in each of the planes of memory array 200-d. Forexample, a selective etching operation may be performed to form theplurality of recesses 315 in sidewalls 390 and 391 of the trench 350 inan isotropic way. In some examples, the trench 350 includes a firstsidewall 390 spaced apart from a second sidewall 391, where a firstportion 392 of the first sidewall 390 formed by the first insulativematerial 240 is spaced apart from a first portion 393 of the secondsidewall 391 formed by the first insulative material 240 by a firstdistance. A second portion 394 of the first sidewall 390 formed by thefirst conductive material 245 may be spaced apart from a second portion394 of the second sidewall 391 formed by the first conductive material245 by a second distance greater than the first distance. In someexamples, portions of sidewalls 390 and 391 of the trench 350 formed bythe first conductive material 245 are recessed relative to portions ofthe sidewalls 390 and 391 of the trench 350 formed by the firstinsulative material 240.

The etching operations may include one or more vertical etchingprocesses (e.g., an anisotropic etching process or a dry etchingprocess, or a combination thereof) or horizontal etching processes(e.g., an isotropic etching process) or combinations thereof. Forexample, a vertical etching process may be performed to vertically etchthe trench 350 and a horizontal etching process may be used to form atleast one recess 315 in at least one conductive material 245. Theetching parameters may be selected such that the conductive material245, for example, is etched faster than the second insulative material240.

FIG. 3C illustrates forming a conformal material 320 (e.g., asacrificial material or sacrificial layer). The conformal material 320may be deposited into the trench 350 of memory array 200-e. Theconformal material 320 may be formed in the recesses 315 (shown in FIG.3B) by conformally depositing the conformal material 320. The conformalmaterial 320 contacts a first sidewall 390, a second sidewall 391, and abottom wall 395 of each trenches 350. Although FIG. 3C shows theconformal material 320 may be formed on the sidewalls of the trench 350(e.g., on the surfaces of the second insulative material 240 and theconductive materials 245 in different layers facing into the trench 350)during formation of the conformal material 320 in the plurality ofrecesses 315, examples are not so limited. For example, the conformalmaterial 320 may be confined to only the plurality of recesses 315 inthe conductive materials 245 in different layers in some cases. In somecases, the conformal material 320 may be referred to as a conformallayer or a sacrificial layer.

In some cases, an etching operation may be performed subsequent toforming the conformal material 320. In the etching operation, theconformal material 320 may be etched to form an opening or trench 350.The etch operation may result in the surfaces of the conformal material320 (e.g., the surfaces facing the trench 350) being spaced apart fromthe surfaces of the second insulative material 240 (e.g., the surfacesfacing into the trench 350). In some cases, the etch operation mayresult in the surfaces of the conformal material 320 (e.g., the surfacesfacing the trench 350) being approximately coplanar with surfaces of thesecond insulative material 240 (e.g., the surfaces facing into thetrench 350), and thereby forming a continuous sidewall of trench. Theetching operations described herein may be vertical etching processes(e.g., an anisotropic etching process or a dry etching process, or acombination thereof) or horizontal etching processes (e.g., an isotropicetching process). For example, a vertical etching process may beperformed to vertically etch the trench 350 and a horizontal etchingprocess may be used to form at least one recess in the first conductivematerial 245.

FIG. 3D illustrates depositing a dielectric material 318 in the trench350 on top of the conformal material 320 of the memory array 200-f. Thedielectric material 318 may contact the conformal material 320. Thedielectric material 318 and the conformal material 320 may cooperate tofill the trench 350. In some cases, the dielectric material 318 may bean example of an insulative material. In some examples, the conformalmaterial 320 may be etched back selectively to form a co-planar surfacewith the dielectric material 318. The depth of the recession may bedefined depending on a desired thickness.

FIG. 3E illustrates a top view of an example 3D memory array 200-f afterthe dielectric material 318 is deposited (as shown in FIG. 3D), inaccordance with an example of the present disclosure. In FIG. 3E, theconformal material 320 formed in the trench 350 and the dielectricmaterial 318 bifurcates each plane of the conductive material 245 into afirst portion 308 and a second portion 309.

FIGS. 4A-E illustrates various views of example 3D memory arrays 200-g,200-h, 200-i, and 200-j, during a series of steps or processes that maybe performed to form a stacked memory device, in accordance withexamples as disclosed herein. Specifically, FIGS. 4A-E illustrateprocesses for forming memory cells in the memory array 200-f illustratedin FIGS. 3D and 3E.

FIG. 4A illustrates a top view of a memory array 200-g, which may be anexample of the memory array 200-f illustrated in FIG. 3E after formationof openings 360. FIG. 4B illustrates a cross-sectional view of anexample 3D memory array 200-h along section line A-A′ during a processstep subsequent to what is illustrated in FIG. 4A. FIG. 4C illustrates across-sectional view of an example 3D memory array 200-i along sectionline A-A′ during a process step subsequent to what is illustrated inFIG. 4B. FIG. 4D illustrates a cross-sectional view of an example 3Dmemory array 200-j along section line A-A′ during a process stepsubsequent to what is illustrated in FIG. 4C. FIG. 4E illustrates a topview of the example 3D memory array 200-j of section line B-B′ during aprocess step subsequent to what is illustrated in FIG. 4C.

FIG. 4A illustrates a top view through any one of the planes of theconductive material 245 of the memory array 200-g. A plurality ofopenings 360 in a trench 350 may be formed by etching away a portion ofthe dielectric material 318 and/or the conformal material 320. Theopenings 360 are intended to be positioned in alignment with theplurality of contacts 235 so that forming the openings 360 exposes atleast a portion of a plurality of contacts 235 (shown in FIG. 4B)extending through the substrate 104 (shown in FIG. 4B). The etchingprocess may be a vertical etching process. In some examples, the etchingoperation may not etch away all portions of the conformal material 320,for example, where the plurality of openings 360 are not formed.

FIG. 4B illustrates a cross-sectional view of an example 3D memory array200-h in accordance with an example of the present disclosure. As shownin FIG. 4B, a plurality of recesses 315 may be formed in the conductivematerial 245 in each of the planes. For example, a selective etchingoperation may be performed to form the plurality of recesses 315 in afull or partially isotropic way. The etching chemistry may be selectedto selectively reach a conductive material 245. The contacts 235 may beexposed by forming the openings 360 in in the trench 350.

FIG. 4C illustrates a cross-sectional view of an example 3D memory array200-i in accordance with an example of the present disclosure. As shownin FIG. 4C, a storage element material 465 may be formed in theplurality of recesses 315 by conformally depositing the storage elementmaterial 465 into the trench 350. The storage element material 465 maybe deposited to contact sidewalls 390 and 391 and a bottom wall 395 ofthe trench 350 exposed by the etching of the conformal material 320.When the storage element material 465 contacts the bottom wall 395 ofthe trench 350, the storage element material 465 covers the exposedcontacts 235.

The storage element material 465 may be an example of a chalcogenidematerial, such as a chalcogenide alloy and/or glass, that may serve as aself-selecting storage element material (e.g., a material that may serveas both a select device and a storage element). For example, the storageelement material 465 may be responsive to an applied voltage, such as aprogram pulse. For an applied voltage that is less than a thresholdvoltage, the storage element material 465 may remain in an electricallynonconductive state (e.g., an “off” state). Alternatively, responsive toan applied voltage that is greater than the threshold voltage, thestorage element material 465 may enter an electrically conductive state(e.g., an “on” state).

The storage element material 465 may be programmed to a target state byapplying a pulse (e.g., a programming pulse) that satisfies aprogramming threshold. The amplitude, shape, or other characteristics ofthe programming pulse may be configured to cause the storage elementmaterial 465 to exhibit the target state. For example, after applyingthe programming pulse, the ions of the storage element material 465 maybe redistributed throughout the storage element, thereby altering aresistance of the memory cell detected when a read pulse is applied. Insome cases, the threshold voltage of the storage element material 465may vary based on applying the programming pulse.

The state stored by the storage element material 465 may be sensed,detected, or read by applying read pulse to the storage element material465. The amplitude, shape, or other characteristics of the read pulsemay be configured to allow a sense component to determine what state isstored on the storage element material 465. For example, in some cases,the amplitude of the read pulse is configured to be at a level that thestorage element material 465 will be in an “on” state (e.g., current isconducted through the material) for a first state but will be in an“off” state (e.g., little to no current is conducted through thematerial) for a second state.

In some cases, the polarity of the pulse (whether programming or read)applied to the storage element material 465 may affect the outcomes ofthe operation being performed. For example, if the storage elementmaterial 465 stores a first state, a read pulse of a first polarity mayresult in the storage element material 465 exhibiting an “on” statewhile a read pulse of a second polarity may result in the storageelement material 465 exhibiting an “off” state. This may occur becauseof the asymmetrical distributions of ions or other material in thestorage element material 465 when it is storing a state. Similarprinciples apply to programming pulses and other pulses or voltages.

Examples of chalcogenide materials that may serve as the storage elementmaterial 465 include indium(In)-antimony(Sb)-tellurium(Te) (IST)materials, such as In₂Sb₂Te₅, In₁Sb₂Te₄, In₁Sb₄Te₇, etc., andgermanium(Ge)-antimony(Sb)-tellurium(Te) (GST) materials, such asGe₈Sb₅Te₈, Ge₂Sb₂Te₅, Ge₁Sb₂Te₄, Ge₁Sb₄Te₇, Ge₄Sb₄Te₇, or etc., amongother chalcogenide materials, including, for instance, alloys that donot change phase during the operation (e.g., selenium-based chalcogenidealloys). Further, the chalcogenide material may include minorconcentrations of other dopant materials. Other examples of chalcogenidematerials may include tellurium-arsenic (As)-germanium (OTS) materials,Ge, Sb, Te, silicon (Si), nickel (Ni), gallium (Ga), As, silver (Ag),tin (Sn), gold (Au), lead (Pb), bismuth (Bi), indium (In), selenium(Se), oxygen (O), Sulphur (S), nitrogen (N), carbon (C), yttrium (Y),and scandium (Sc) materials, and combinations thereof. The hyphenatedchemical composition notation, as used herein, indicates the elementsincluded in a particular mixture or compound, and is intended torepresent all stoichiometries involving the indicated elements. In someexamples, the chalcogenide material may be a chalcogenide glass oramorphous chalcogenide material. In some example, a chalcogenidematerial having primarily selenium (Se), arsenic (As), and germanium(Ge) may be referred to as SAG-alloy. In some examples, SAG-alloy mayinclude silicon (Si) and such chalcogenide material may be referred toas SiSAG-alloy. In some examples, the chalcogenide glass may includeadditional elements such as hydrogen (H), oxygen (O), nitrogen (N),chlorine (Cl), or fluorine (F), each in atomic or molecular forms. Insome examples, conductivity may be controlled through doping usingvarious chemical species. For example, doping may include incorporatinga Group 3 (e.g., boron (B), gallium (Ga), indium (In), aluminum (Al),etc.) or Group 4 (tin (Sn), carbon (C), silicon (Si), etc.) element intothe composition.

FIG. 4D illustrates a cross-sectional view of an example 3D memory array200-j in accordance with an example of the present disclosure. Anetching operation may be performed subsequent to forming the storageelement material 465 so that surfaces of the storage element material465 (e.g., the surfaces facing into the trench 350) is approximatelycoplanar with surfaces of the second insulative material 240 (e.g., thesurfaces facing into the trench 350) as illustrated in FIG. 4D. Theetching of the storage element material 465 may form a continuoussidewall and remove the top layer 466 (shown in FIG. 4C) of the storageelement material 465, whereby cells of the storage element material 465are formed in the recesses only. In each recess, each cell of thestorage element material 465 may contact a single conductive material245 (e.g., a single conductive material 245 located adjacent to the cellof the storage element material 465) and at least two dielectric layers(e.g. a top dielectric layer and a bottom dielectric layer located ontop of the cell of the storage element material 465 and on bottom of thecell of the storage element material 465), as shown in FIG. 4D. Theetching of the storage element material 465 may provide a configurationin which the storage element material 465 are separated from oneanother. The etching of the storage element material 465 may also exposethe contacts 235 in the substrate 104. In some examples, portion ofsacrificial material may be located on either side of the cell of thestorage element material 465 (as shown in FIG. 4E).

FIG. 4E illustrates a top view of an example 3D memory array 200-j inaccordance with an example of the present disclosure. As illustrated inFIG. 4E, the conformal material 320 and the storage element material 465formed in the trench 350 may bifurcate each plane of the conductivematerial 245 into a first portion 308 and a second portion 309. Eachportion of a plane may be an example of a word line plate.

FIGS. 5A-C illustrates various views of example 3D memory arrays 200-kand 200-l, during a series of steps or processes that may be performedto form a stacked memory device, in accordance with examples asdisclosed herein. Specifically, FIGS. 5A-C illustrate processes offilling the openings 360 after the recessed self-selecting memory cellsare formed.

FIG. 5A illustrates a top view of a memory array 200-k, which may be anexample of the memory array 200-j illustrated in FIG. 4E after formationof recessed self-selecting memory cells. FIG. 5B is a top view of amemory array 200-l through any one of the planes of the conductivematerial 245 illustrated in FIG. 4E during a processing step that issubsequent to what is illustrated in FIG. 5A. FIG. 5C illustrates across-sectional view of an example 3D memory array 200-m along sectionline A-A′ during a processing step that is subsequent to what isillustrated in FIG. 5B.

FIG. 5A illustrates a top view of a memory array 200-k where a barriermaterial 570 is deposited into the openings 360 of the trench 350. Insome implementations, the barrier material 570 contacts at least oneportion of the first insulative material 240 (not shown), the secondinsulative material 240 (not shown), and the storage element material465. In some examples, the barrier material 570 is compatible with anactive material. In some examples, the barrier material 570 may be aconductive material, or a barrier layer with a conductive material. Thebarrier layer may comprise aluminum oxide, for example. In someexamples, an etching operation may be performed to make room forconductive material to be deposited into the trench 350. In some cases,the barrier material 570 may be referred to as a barrier layer.

FIG. 5B illustrates a top view of a memory array 200-l where aconductive material 575 is deposited into the openings 360 of the trench350. A conductive material 575 may deposited in the opening 360 to forma conductive pillar 580. The conductive pillar 580 may include thebarrier material 570 and the conductive material 575. In some examples,the conductive pillar 580 may be formed in contact with the storageelement material 465 on the sidewalls 390 and 391 (shown in FIG. 4C) ofthe trench 350. In some examples, the conductive pillar 580 may comprisethe same material as the conductive material 575. In some examples, theconductive pillar 580 may be a digit line. The conductive pillar 580 maybe a cylinder. Although FIG. 5D illustrates the conductive pillar 580 asa solid pillar, in some examples the conductive pillar 580 may be ahollow cylinder or toroidal (e.g., a tube). The conductive pillar 580may comprise a metallic (or semi-metallic) material or a semiconductormaterial such as a doped polysilicon material, among others. However,other metallic, semi-metallic, or semiconductor materials may be used.

The conductive pillar 580 formed in each respective one of the pluralityof openings 360 are arranged to extend substantially orthogonal to thealternating planes of the conductive material 245 and the secondinsulative material 240 (not shown). The storage element material 465and the conductive pillar 580 formed in each respective one of theplurality of openings 360 are formed in a substantially square shape.However, examples of the present disclosure are not limited to exact orquasi-exact square shapes. For instance, the storage element material465 and the conductive pillar 580 may formed in any shape, includingcircles or oval shapes, for instance.

FIG. 5C illustrates a side view of an example 3D memory array 200-m inaccordance with an example of the present disclosure. As illustrated inFIG. 5C, a capping layer 585 (e.g., an insulative material, such as adielectric layer) may be deposited to cap the conductive pillars 580 ofmemory array 200-l.

The memory array 200-m may include a plurality of vertical stacks. Eachrespective stack may include the conductive pillar 580, a conductivecontact 235 coupled to the conductive pillar 580, the storage elementmaterial 465 formed in contact with the first portion 308 and theconductive pillar 580, and the storage element material 465 formed incontact with the second portion 309 and the conductive pillar 580.

The conductive pillar 580 may be in contact with the conductive contact235 and the first insulative material 240, and in contact with thestorage element material 465 formed in the recesses 315. In some cases,the storage element material 465 formed in each respective recess 315 isformed partially (e.g., not completely) around the conductive pillar580.

Although not shown in FIG. 5C for clarity and so as not to obscureexamples of the present disclosure, other materials may be formedbefore, after, and/or between the storage element material 465, and/orthe conductive pillar 580, for example, to form adhesion layers orbarriers against interdiffusion of materials and/or to mitigatecomposition mixing.

FIGS. 6A-B illustrates various views of example 3D memory arrays 600-aand 600-b, which may be examples of the 3D memory arrays 200-a through200-m processed in FIGS. 2A-5C, in accordance with examples as disclosedherein. The memory arrays 600-a and 600-b may include similar featuresas memory arrays 200-a through 200-m described with reference to FIGS.2A-5C. A plurality of openings 360 may be formed through the alternatingplanes of the conductive material 245 and the second insulative material240 (not shown), and the dielectric material 318 in the trench 350. Asshown, the diameter of the plurality of openings 360 is approximatelythe same width of the trench 350. In some examples, the diameter of theplurality of openings 360 may be greater than the width of the trench350.

Each of the plurality of openings 360 may be approximately concentricwith a different respective one of the conductive contacts 235. As shownin FIGS. 6A and 6B, the pillars 580 are circular and formed over andcoupled to the plurality of contacts in geometric pattern in respectiveopenings 360. In some examples, such as illustrated in FIGS. 2A-3E, theopenings 360 may be square.

The plurality of openings 360 may have the staggered (e.g., hexagonal)arrangement of the conductive contacts 235 (not shown). For example, arespective one of the plurality of conductive contacts 235 may besurrounded by six other conductive contacts 235.

A staggered pattern may refer to any pattern where positions of objects(e.g., contacts, openings, or pillars) in a first row are offset frompositions of objects (e.g., contacts, openings, or pillars) in a secondrow adjacent to the first row in a given direction. For example, astaggered pattern may have objects (e.g., contacts, openings, orpillars) adjacent to one another in the x-direction (e.g., rows), butnot in the y-direction (e.g., columns). For instance, as illustrated inFIGS. 6A and 6B, the plurality of conductive contacts 235 are adjacentto each other and in line with each other in an x-direction. However,the plurality of conductive contacts 235 are not adjacent to each otherin the y-direction. The plurality of conductive contacts 235 are in linewith each other in the x-direction and the plurality of conductivecontacts 235 alternate (e.g., skip) rows in the y-direction. Although,FIGS. 6A and 6B show spacing that is approximately the same between theconductive contacts 235 throughout the substrate 104, examples inaccordance with the present disclosure are not so limited. For example,the spacing between the conductive contacts 235 may vary throughout thesubstrate 104.

FIG. 6B shows that the 3D memory array may include a plurality ofstorage element materials 465, each comprising a chalcogenide materialpositioned between at least one of the word line plates, at least onecircular pillar 580, and at least one dielectric material 318. In someexamples, depending on the decoding optimization, the pillars 580 may becoupled to a plurality of selectors positioned at a top, a bottom, orboth a top and a bottom (e.g., below or above the plurality of word lineplates) of the 3D memory arrays 600-a or 600-b.

FIGS. 7A-B illustrates various views of example 3D memory arrays 700,which may be examples of the 3D memory arrays 200-a through 200-mprocessed in FIGS. 2A-5C, in accordance with examples as disclosedherein. A plurality of openings 360 may be formed through thealternating planes of the conductive material 245 and the secondinsulative material 240, and the dielectric material 318 in the trench350. As shown, the diameter of the plurality of openings 360 isapproximately the same width of the trench 350. In some examples, thediameter of the plurality of openings 360 may be greater than the widthof the trench 350.

Each of the plurality of openings 360 may be approximately concentricwith a different respective one of the conductive contacts 235. As shownin FIGS. 7A and 7B, the pillars 580 are rectangular oblique and formedover and coupled to the plurality of contacts in geometric pattern inrespective openings 360.

The plurality of openings 360 may have the staggered (e.g., hexagonal)arrangement of the conductive contacts 235. For example, a respectiveone of the plurality of conductive contacts 235 may be surrounded by sixother conductive contacts 235.

As used herein, “a staggered pattern” may refer to a plurality ofconductive contacts that are adjacent to one another one direction butnot in another direction. For example, a staggered pattern may haveobjects (e.g., contacts, openings, or pillars) adjacent to one anotherin the x-direction (e.g., rows), but not in the y-direction (e.g.,columns).

For instance, as illustrated in FIGS. 7A and 7B, the plurality ofconductive contacts 235 are adjacent to each other and in line with eachother in an x-direction. However, the plurality of conductive contacts235 are not adjacent to each other in the y-direction. The plurality ofconductive contacts 235 are in line with each other in the x-directionand the plurality of conductive contacts 235 alternate (e.g., skip) rowsin the y-direction. Although, FIGS. 7A and 7B show spacing that isapproximately the same between the conductive contacts 235-a throughoutthe substrate 104, examples in accordance with the present disclosureare not so limited. For example, the spacing between the conductivecontacts 235-a may vary throughout the substrate 104.

FIG. 7B shows that the 3D memory array may include a plurality ofstorage element materials 465, each comprising a chalcogenide materialpositioned between at least one of the word line plates, at least onerectangular oblique pillar 580, and at least one dielectric material318.

In some examples, depending on the decoding optimization, the pillars580 may be coupled to a plurality of selectors positioned at a top, abottom, or both a top and a bottom (e.g., below or above the pluralityof word line plates) of the 3D memory arrays 700. Spatially relatedterms, including but not limited to, “top,” “bottom,” “lower,” “upper,”“beneath,” “below,” “above,” etc., if used herein, are utilized for easeof description to describe spatial relationships of an element(s) toanother. Such spatially related terms encompass different orientationsof the device in addition to the particular orientations depicted in thefigures and described herein. For example, if a structure depicted inthe figures is turned over or flipped over, portions previouslydescribed as below or beneath other elements would then be above or overthose other elements.

FIG. 8 shows a flowchart illustrating a method or methods 800 thatsupports architecture of three-dimensional memory device and methodsregarding the same in accordance with aspects of the present disclosure.The operations of method 800 may be implemented by a manufacturingsystem or one or more controllers associated with a manufacturingsystem. In some examples, one or more controllers may execute a set ofinstructions to control one or more functional elements of themanufacturing system to perform the described functions. Additionally oralternatively, one or more controllers may perform aspects of thedescribed functions using special-purpose hardware.

At 805, the method 800 may include forming a trench through a firstdielectric layer, a first conductive layer, and a second dielectriclayer, the trench exposing a substrate and dividing the first conductivelayer into a first portion associated with a first word line driver anda second portion associated with a second word line driver. Theoperations of 805 may be performed according to the methods describedherein.

At 810, the method 800 may include depositing a conformal material thatcontacts a first sidewall and a second sidewall of the trench. Theoperations of 810 may be performed according to the methods describedherein.

At 815, the method 800 may include forming an opening over a contactextending through the substrate by etching a portion of the conformalmaterial. The operations of 815 may be performed according to themethods described herein.

At 820, the method 800 may include depositing, into the opening, achalcogenide material configured to store information in contact with asidewall and a bottom wall of the opening exposed by the etching. Theoperations of 820 may be performed according to the methods describedherein.

In some examples, an apparatus as described herein may perform a methodor methods, such as the method 800. The apparatus may include features,means, or instructions (e.g., a non-transitory computer-readable mediumstoring instructions executable by a processor) for forming a trenchthrough a first dielectric layer, a first conductive layer, and a seconddielectric layer, the trench exposing a substrate and dividing the firstconductive layer into a first portion associated with a first word linedriver and a second portion associated with a second word line driver,depositing a conformal material that contacts a first sidewall and asecond sidewall of the trench, forming an opening over a contactextending through the substrate by etching a portion of the conformalmaterial, and depositing, into the opening, a chalcogenide materialconfigured to store information in contact with a sidewall and a bottomwall of the opening exposed by the etching.

Some examples of the method 800 and the apparatus described herein mayfurther include operations, features, means, or instructions fordepositing a dielectric material in the trench that contacts theconformal material, where forming the opening includes etching a portionof the dielectric material. Some examples of the method 800 and theapparatus described herein may further include operations, features,means, or instructions for forming a set of contacts extending throughthe substrate, the set of contacts may be associated with a set of digitlines, forming the first dielectric layer on the substrate, forming thefirst conductive layer on the first dielectric layer, the firstconductive layer configured as at least one word line plate, and formingthe second dielectric layer on the first conductive layer, where formingthe trench may be based on forming the second dielectric layer.

Some examples of the method 800 and the apparatus described herein mayfurther include operations, features, means, or instructions for etchinga portion of the chalcogenide material to form a continuous sidewall ofthe opening, and depositing a barrier material into the opening thatcontacts the continuous sidewall of the opening. In some examples of themethod 800 and the apparatus described herein, the chalcogenide materialincludes a first wall contacting the first conductive layer, a secondwall contacting the first dielectric layer, a third wall contacting thesecond dielectric layer, and a fourth wall contacting the barriermaterial. In some examples of the method 800 and the apparatus describedherein, the barrier material contacts at least one portion of the firstdielectric layer, the second dielectric layer, and the chalcogenidematerial.

Some examples of the method 800 and the apparatus described herein mayfurther include operations, features, means, or instructions for etchingthe barrier material to expose the contact, and depositing a conductivematerial into the opening that contacts the barrier material and thecontact. Some examples of the method 800 and the apparatus describedherein may further include operations, features, means, or instructionsfor forming a second dielectric material over the second dielectriclayer and the conductive material.

In some examples of the method 800 and the apparatus described herein,the conductive material may be configured as a digit line. In someexamples of the method 800 and the apparatus described herein, formingthe trench through the first dielectric layer may include operations,features, means, or instructions for performing a vertical etchingprocess to vertically etch the trench, and performing a horizontaletching process after the vertical etching process to form at least onerecess in the first conductive layer. In some examples of the method 800and the apparatus described herein, the vertical etching processincludes an anisotropic etching process or a dry etching process or acombination thereof. In some examples of the method 800 and theapparatus described herein, the horizontal etching process includes anisotropic etching process.

Some examples of the method 800 and the apparatus described herein mayfurther include operations, features, means, or instructions for forminga set of openings over a set of contacts extending through thesubstrate, and filling the set of openings with a barrier material. Someexamples of the method 800 and the apparatus described herein mayfurther include operations, features, means, or instructions for formingthe trench exposes at least a portion of a set of contacts extendingthrough the substrate.

In some examples of the method 800 and the apparatus described herein,the trench extends through the first conductive layer in a serpentineshape. In some examples of the method 800 and the apparatus describedherein, the trench including the first sidewall spaced apart from thesecond sidewall, where a first portion of the first sidewall formed bythe first dielectric layer may be spaced apart from a first portion ofthe second sidewall formed by the first dielectric layer by a firstdistance, and a second portion of the first sidewall formed by the firstconductive layer may be spaced apart from a second portion of the secondsidewall formed by the first conductive layer by a second distancegreater than the first distance.

Some examples of the method 800 and the apparatus described herein mayfurther include operations, features, means, or instructions forportions of sidewalls of the trench formed by the first conductive layermay be recessed relative to portions of the sidewalls of the trenchformed by the first dielectric layer. In some examples of the method 800and the apparatus described herein, the chalcogenide material includes astorage element for a self-selecting memory cell.

Some examples of the method 800 and the apparatus described herein mayfurther include operations, features, means, or instructions for forminga second conductive layer on the second dielectric layer, the secondconductive layer configured as at least one word line plate, and forminga third dielectric layer on the second conductive layer, where formingthe trench may be based on forming the third dielectric layer. In someexamples of the method 800 and the apparatus described herein, an arrayof memory cells associated with the first conductive layer and thesecond conductive layer includes a three-dimensional array of memorycells.

FIG. 9 shows a flowchart illustrating a method or methods 900 thatsupports architecture of three-dimensional memory device and methodsregarding the same in accordance with aspects of the present disclosure.The operations of method 900 may be implemented by a manufacturingsystem or one or more controllers associated with a manufacturingsystem. In some examples, one or more controllers may execute a set ofinstructions to control one or more functional elements of themanufacturing system to perform the described functions. Additionally oralternatively, one or more controllers may perform aspects of thedescribed functions using special-purpose hardware.

At 905, the method 900 may include forming a set of contacts extendingthrough the substrate, the set of contacts is associated with a set ofdigit lines. The operations of 905 may be performed according to themethods described herein.

At 910, the method 900 may include forming the first dielectric layer onthe substrate. The operations of 910 may be performed according to themethods described herein.

At 915, the method 900 may include forming the first conductive layer onthe first dielectric layer, the first conductive layer configured as atleast one word line plate. The operations of 915 may be performedaccording to the methods described herein.

At 920, the method 900 may include forming the second dielectric layeron the first conductive layer, where forming the trench is based onforming the second dielectric layer. The operations of 920 may beperformed according to the methods described herein.

At 925, the method 900 may include forming a trench through a firstdielectric layer, a first conductive layer, and a second dielectriclayer, the trench exposing a substrate and dividing the first conductivelayer into a first portion associated with a first word line driver anda second portion associated with a second word line driver. Theoperations of 925 may be performed according to the methods describedherein.

At 930, the method 900 may include depositing a conformal material thatcontacts a first sidewall and a second sidewall of the trench. Theoperations of 930 may be performed according to the methods describedherein.

At 935, the method 900 may include forming an opening over a contactextending through the substrate by etching a portion of the conformalmaterial. The operations of 935 may be performed according to themethods described herein.

At 940, the method 900 may include depositing, into the opening, achalcogenide material configured to store information in contact with asidewall and a bottom wall of the opening exposed by the etching. Theoperations of 940 may be performed according to the methods describedherein.

FIG. 10 shows a flowchart illustrating a method or methods 1000 thatsupports architecture of three-dimensional memory device and methodsregarding the same in accordance with aspects of the present disclosure.The operations of method 1000 may be implemented by a manufacturingsystem or one or more controllers associated with a manufacturingsystem. In some examples, one or more controllers may execute a set ofinstructions to control one or more functional elements of themanufacturing system to perform the described functions. Additionally oralternatively, one or more controllers may perform aspects of thedescribed functions using special-purpose hardware.

At 1005, the method 1000 may include forming a trench through a firstdielectric layer, a first conductive layer, and a second dielectriclayer, the trench exposing a substrate and dividing the first conductivelayer into a first portion associated with a first word line driver anda second portion associated with a second word line driver. Theoperations of 1005 may be performed according to the methods describedherein.

At 1010, the method 1000 may include depositing a conformal materialthat contacts a first sidewall and a second sidewall of the trench. Theoperations of 1010 may be performed according to the methods describedherein.

At 1015, the method 1000 may include forming an opening over a contactextending through the substrate by etching a portion of the conformalmaterial. The operations of 1015 may be performed according to themethods described herein.

At 1020, the method 1000 may include depositing, into the opening, achalcogenide material configured to store information in contact with asidewall and a bottom wall of the opening exposed by the etching. Theoperations of 1020 may be performed according to the methods describedherein.

At 1025, the method 1000 may include etching a portion of thechalcogenide material to form a continuous sidewall of the opening. Theoperations of 1025 may be performed according to the methods describedherein.

At 1030, the method 1000 may include depositing a barrier material intothe opening that contacts the continuous sidewall of the opening. Theoperations of 1030 may be performed according to the methods describedherein.

FIG. 11 shows a flowchart illustrating a method or methods 1100 thatsupports architecture of three-dimensional memory device and methodsregarding the same in accordance with aspects of the present disclosure.The operations of method 1100 may be implemented by a manufacturingsystem or one or more controllers associated with a manufacturingsystem. In some examples, one or more controllers may execute a set ofinstructions to control one or more functional elements of themanufacturing system to perform the described functions. Additionally oralternatively, one or more controllers may perform aspects of thedescribed functions using special-purpose hardware.

At 1105, the method 1100 may include forming a set of contactsassociated with a set of digit lines extending through a substrate. Theoperations of 1105 may be performed according to the methods describedherein.

At 1110, the method 1100 may include forming a first dielectric layer onthe substrate. The operations of 1110 may be performed according to themethods described herein.

At 1115, the method 1100 may include forming a first conductive layer onthe first dielectric layer, the first conductive layer configured as atleast one word line plate. The operations of 1115 may be performedaccording to the methods described herein.

At 1120, the method 1100 may include forming a second dielectric layeron the first conductive layer. The operations of 1120 may be performedaccording to the methods described herein.

At 1125, the method 1100 may include forming at least one trench throughthe first dielectric layer, the first conductive layer, and the seconddielectric layer, the at least one trench dividing the first conductivelayer into a first portion associated with a first word line driver anda second portion associated with a second word line driver. Theoperations of 1125 may be performed according to the methods describedherein.

At 1130, the method 1100 may include depositing a conformal material tocontact a first sidewall, a second sidewall, and a bottom wall of eachof the set of trenches. The operations of 1130 may be performedaccording to the methods described herein.

At 1135, the method 1100 may include forming a circular opening in eachof the set of trenches over a contact of the set of contacts by etchinga portion of the conformal material. The operations of 1135 may beperformed according to the methods described herein.

At 1140, the method 1100 may include depositing, into the circularopening, a chalcogenide material that contacts surfaces of the firstsidewall, the second sidewall, and the bottom wall in each of the set oftrenches, the chalcogenide material configured to store information. Theoperations of 1140 may be performed according to the methods describedherein.

In some examples, an apparatus as described herein may perform a methodor methods, such as the method 1100. The apparatus may include features,means, or instructions (e.g., a non-transitory computer-readable mediumstoring instructions executable by a processor) for forming a set ofcontacts associated with a set of digit lines extending through asubstrate, forming a first dielectric layer on the substrate, forming afirst conductive layer on the first dielectric layer, the firstconductive layer configured as at least one word line plate, forming asecond dielectric layer on the first conductive layer, forming at leastone trench through the first dielectric layer, the first conductivelayer, and the second dielectric layer, the at least one trench dividingthe first conductive layer into a first portion associated with a firstword line driver and a second portion associated with a second word linedriver, depositing a conformal material to contact a first sidewall, asecond sidewall, and a bottom wall of each of the set of trenches,forming a circular opening in each of the set of trenches over a contactof the set of contacts by etching a portion of the conformal material,and depositing, into the circular opening, a chalcogenide material thatcontacts surfaces of the first sidewall, the second sidewall, and thebottom wall in each of the set of trenches, the chalcogenide materialconfigured to store information. Some examples of the method 1100 andthe apparatus described herein may further include operations, features,means, or instructions for forming a set of pillars over the set ofcontacts in a hexagonal pattern, and coupling the set of pillars with aset of selectors positioned in at least at one of a top and a bottom ofthe apparatus.

It should be noted that the methods described above describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Furthermore, portions from two or more of the methods may be combined.

An apparatus is described. The apparatus may include a set of contactsassociated with a set of digit lines and extending through a substrate,a second set of word line plates separated from a first set of word lineplates, a dielectric material positioned between the first set and thesecond set of word line plates, the dielectric material extending in aserpentine shape over the substrate, a set of pillars formed over andcoupled with the set of contacts, and a set of storage elements eachincluding chalcogenide material positioned in a recess formed by atleast one word line plate, at least one pillar, and at least onedielectric layer.

Some examples of the apparatus may include a conformal materialextending between a first chalcogenide material and a secondchalcogenide material in recesses between word line plates of first setof word line plates and contacting the dielectric material. In someexamples, the conformal material may be positioned between word lineplates of the first set of word line plates and the dielectric material.In some examples, a pillar of the set of pillars further includes abarrier layer contacting at least portions of the chalcogenide materialand a conductive material contacting the barrier layer and configured asa digit line. In some examples, the barrier layer includes an aluminumoxide.

Some examples may further include at least one of the first set of wordline plates and the second set of word line plates includes a conductivematerial. In some examples, the set of pillars formed over the set ofcontacts interrupts a continuity of the dielectric material extendingover the substrate in the serpentine shape. In some examples, the set ofcontacts may be arranged in a staggered pattern. In some examples, theset of contacts may be arranged in a grid.

An apparatus is described. The apparatus may include a set of contactsassociated with a set of digit lines extending through a substrate andarranged in a geometric pattern, a dielectric material separating afirst set of a set of word lines plates from a second set of the set ofword line plates, a set of circular pillars formed over the set ofcontacts and arranged in a geometric pattern, each circular pillar ofthe set of circular pillars coupled with a contact of the set ofcontacts, and a set of storage elements each including a chalcogenidematerial positioned between at least one of the word line plates, atleast one circular pillar, and at least one dielectric layer. In someexamples, the set of circular pillars may be coupled with a set ofselectors positioned below the substrate or above the set of word lineplates.

An apparatus is described. The apparatus may include a set of contactsassociated with a set of digit lines extending through a substrate andarranged in a hexagonal pattern, a second word line plate positioned ata same level as a first word line plate and spaced apart from the firstword line plate, a dielectric material extending in a serpentine shapeover the substrate and positioned between the first word line plate andthe second word line plate, a set of rectangular oblique pillars formedover the set of contacts and arranged in a hexagonal pattern, eachrectangular oblique pillar coupled with a contact of the set ofcontacts, and a set of storage elements including a chalcogenidematerial positioned in a recess between at least one of the word lineplates, at least one rectangular oblique pillar, and at least onedielectric layer. In some examples, the set of rectangular obliquepillars may be coupled with a set of selectors positioned below thesubstrate or above the first word line plate.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof. Some drawings may illustrate signals as a single signal;however, it will be understood by a person of ordinary skill in the artthat the signal may represent a bus of signals, where the bus may have avariety of bit widths.

As used herein, the term “virtual ground” refers to a node of anelectrical circuit that is held at a voltage of approximately zero volts(0V) but that is not directly coupled with ground. Accordingly, thevoltage of a virtual ground may temporarily fluctuate and return toapproximately 0V at steady state. A virtual ground may be implementedusing various electronic circuit elements, such as a voltage dividerconsisting of operational amplifiers and resistors. Otherimplementations are also possible. “Virtual grounding” or “virtuallygrounded” means connected to approximately 0V.

The terms “electronic communication,” “conductive contact,” “connected,”and “coupled” may refer to a relationship between components thatsupports the flow of signals between the components. Components areconsidered in electronic communication with (or in conductive contactwith or connected with or coupled with) one another if there is anyconductive path between the components that may, at any time, supportthe flow of signals between the components. At any given time, theconductive path between components that are in electronic communicationwith each other (or in conductive contact with or connected with orcoupled with) may be an open circuit or a closed circuit based on theoperation of the device that includes the connected components. Theconductive path between connected components may be a direct conductivepath between the components or the conductive path between connectedcomponents may be an indirect conductive path that may includeintermediate components, such as switches, transistors, or othercomponents. In some cases, the flow of signals between the connectedcomponents may be interrupted for a time, for example, using one or moreintermediate components such as switches or transistors.

The term “coupling” refers to condition of moving from an open-circuitrelationship between components in which signals are not presentlycapable of being communicated between the components over a conductivepath to a closed-circuit relationship between components in whichsignals are capable of being communicated between components over theconductive path. When a component, such as a controller, couples' othercomponents together, the component initiates a change that allowssignals to flow between the other components over a conductive path thatpreviously did not permit signals to flow.

The term “isolated” refers to a relationship between components in whichsignals are not presently capable of flowing between the components.Components are isolated from each other if there is an open circuitbetween them. For example, two components separated by a switch that ispositioned between the components are isolated from each other when theswitch is open. When a controller isolates two components, thecontroller affects a change that prevents signals from flowing betweenthe components using a conductive path that previously permitted signalsto flow.

The term “layer” used herein refers to a stratum or sheet of ageometrical structure. Each layer may have three dimensions (e.g.,height, width, and depth) and may cover at least a portion of a surface.For example, a layer may be a three-dimensional structure where twodimensions are greater than a third, e.g., a thin-film. Layers mayinclude different elements, components, and/or materials. In some cases,one layer may be composed of two or more sublayers. In some of theappended figures, two dimensions of a three-dimensional layer aredepicted for purposes of illustration. Those skilled in the art will,however, recognize that the layers are three-dimensional in nature.

As used herein, the term “substantially” means that the modifiedcharacteristic (e.g., a verb or adjective modified by the termsubstantially) need not be absolute but is close enough to achieve theadvantages of the characteristic.

As used herein, the term “electrode” may refer to an electricalconductor, and in some cases, may be employed as an electrical contactto a memory cell or other component of a memory array. An electrode mayinclude a trace, wire, conductive line, conductive layer, or the likethat provides a conductive path between elements or components of memoryarray.

The devices discussed herein, including a memory array, may be formed ona semiconductor substrate, such as silicon, germanium, silicon-germaniumalloy, gallium arsenide, gallium nitride, etc. In some cases, thesubstrate is a semiconductor wafer. In other cases, the substrate may bea silicon-on-insulator (SOI) substrate, such as silicon-on-glass (SOG)or silicon-on-sapphire (SOP), or epitaxial layers of semiconductormaterials on another substrate. The conductivity of the substrate, orsub-regions of the substrate, may be controlled through doping usingvarious chemical species including, but not limited to, phosphorous,boron, or arsenic. Doping may be performed during the initial formationor growth of the substrate, by ion-implantation, or by any other dopingmeans.

A switching component or a transistor discussed herein may represent afield-effect transistor (FET) and comprise a three terminal deviceincluding a source, drain, and gate. The terminals may be connected toother electronic elements through conductive materials, e.g., metals.The source and drain may be conductive and may comprise a heavily-doped,e.g., degenerate, semiconductor region. The source and drain may beseparated by a lightly-doped semiconductor region or channel. If thechannel is n-type (i.e., majority carriers are signals), then the FETmay be referred to as a n-type FET. If the channel is p-type (i.e.,majority carriers are holes), then the FET may be referred to as ap-type FET. The channel may be capped by an insulating gate oxide. Thechannel conductivity may be controlled by applying a voltage to thegate. For example, applying a positive voltage or negative voltage to ann-type FET or a p-type FET, respectively, may result in the channelbecoming conductive. A transistor may be “on” or “activated” when avoltage greater than or equal to the transistor's threshold voltage isapplied to the transistor gate. The transistor may be “off” or“deactivated” when a voltage less than the transistor's thresholdvoltage is applied to the transistor gate.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details toproviding an understanding of the described techniques. Thesetechniques, however, may be practiced without these specific details. Insome instances, well-known structures and devices are shown in blockdiagram form to avoid obscuring the concepts of the described examples.

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a digital signal processor (DSP), anapplication-specific integrated circuit (ASIC), a field-programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any processor, controller,microcontroller, or state machine. A processor may also be implementedas a combination of computing devices (e.g., a combination of a DSP anda microprocessor, multiple microprocessors, one or more microprocessorsin conjunction with a DSP core, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described above may be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items (for example, a list of items prefaced by a phrasesuch as “at least one of” or “one or more of”) indicates an inclusivelist such that, for example, a list of at least one of A, B, or C meansA or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, asused herein, the phrase “based on” shall not be construed as a referenceto a closed set of conditions. For example, an exemplary step that isdescribed as “based on condition A” may be based on both a condition Aand a condition B without departing from the scope of the presentdisclosure. In other words, as used herein, the phrase “based on” shallbe construed in the same manner as the phrase “based at least in parton.”

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be apparent to those skilled in the art, and the generic principlesdefined herein may be applied to other variations without departing fromthe scope of the disclosure. Thus, the disclosure is not limited to theexamples and designs described herein, but is to be accorded thebroadest scope consistent with the principles and novel featuresdisclosed herein.

What is claimed is:
 1. A method, comprising: forming a trench through afirst dielectric layer, a first conductive layer, and a seconddielectric layer, the trench exposing a substrate and dividing the firstconductive layer into a first portion associated with a first word linedriver and a second portion associated with a second word line driver;depositing a conformal material that contacts a first sidewall and asecond sidewall of the trench; forming an opening over a contactextending through the substrate by etching a portion of the conformalmaterial; and depositing, into the opening, a chalcogenide materialconfigured to store information in contact with a sidewall and a bottomwall of the opening exposed by the etching.
 2. The method of claim 1,further comprising: depositing a dielectric material in the trench thatcontacts the conformal material, wherein forming the opening includesetching a portion of the dielectric material.
 3. The method of claim 1,further comprising: forming a plurality of contacts extending throughthe substrate, the plurality of contacts is associated with a pluralityof digit lines; forming the first dielectric layer on the substrate;forming the first conductive layer on the first dielectric layer, thefirst conductive layer configured as at least one word line plate; andforming the second dielectric layer on the first conductive layer,wherein forming the trench is based at least in part on forming thesecond dielectric layer.
 4. The method of claim 1, further comprising:etching a portion of the chalcogenide material to form a continuoussidewall of the opening; and depositing a barrier material into theopening that contacts the continuous sidewall of the opening.
 5. Themethod of claim 4, wherein the chalcogenide material comprises a firstwall contacting the first conductive layer, a second wall contacting thefirst dielectric layer, a third wall contacting the second dielectriclayer, and a fourth wall contacting the barrier material.
 6. The methodof claim 4, wherein the barrier material contacts at least one portionof the first dielectric layer, the second dielectric layer, and thechalcogenide material.
 7. The method of claim 4, further comprising:etching the barrier material to expose the contact; and depositing aconductive material into the opening that contacts the barrier materialand the contact.
 8. The method of claim 7, further comprising: forming asecond dielectric material over the second dielectric layer and theconductive material.
 9. The method of claim 7, wherein the conductivematerial is configured as a digit line.
 10. The method of claim 1,wherein forming the trench through the first dielectric layer comprises:performing a vertical etching process to vertically etch the trench; andperforming a horizontal etching process after the vertical etchingprocess to form at least one recess in the first conductive layer. 11.The method of claim 10, wherein the vertical etching process comprisesan anisotropic etching process or a dry etching process or a combinationthereof.
 12. The method of claim 10, wherein the horizontal etchingprocess comprises an isotropic etching process.
 13. The method of claim1, further comprising: forming a plurality of openings over a pluralityof contacts extending through the substrate; and filling the pluralityof openings with a barrier material.
 14. The method of claim 1, whereinforming the trench exposes at least a portion of a plurality of contactsextending through the substrate.
 15. The method of claim 1, wherein thetrench extends through the first conductive layer in a serpentine shape.16. The method of claim 1, wherein the trench comprising the firstsidewall spaced apart from the second sidewall, wherein a first portionof the first sidewall formed by the first dielectric layer is spacedapart from a first portion of the second sidewall formed by the firstdielectric layer by a first distance, and a second portion of the firstsidewall formed by the first conductive layer is spaced apart from asecond portion of the second sidewall formed by the first conductivelayer by a second distance greater than the first distance.
 17. Themethod of claim 1, wherein portions of sidewalls of the trench formed bythe first conductive layer are recessed relative to portions of thesidewalls of the trench formed by the first dielectric layer.
 18. Themethod of claim 1, wherein the chalcogenide material comprises a storageelement for a self-selecting memory cell.
 19. The method of claim 1,further comprising: forming a second conductive layer on the seconddielectric layer, the second conductive layer configured as at least oneword line plate; and forming a third dielectric layer on the secondconductive layer, wherein forming the trench is based at least in parton forming the third dielectric layer.
 20. The method of claim 19,wherein an array of memory cells associated with the first conductivelayer and the second conductive layer comprises a three-dimensionalarray of memory cells.
 21. A method, comprising: forming a plurality ofcontacts associated with a plurality of digit lines extending through asubstrate; forming a first dielectric layer on the substrate; forming afirst conductive layer on the first dielectric layer, the firstconductive layer configured as at least one word line plate; forming asecond dielectric layer on the first conductive layer; forming at leastone trench through the first dielectric layer, the first conductivelayer, and the second dielectric layer, the at least one trench dividingthe first conductive layer into a first portion associated with a firstword line driver and a second portion associated with a second word linedriver; depositing a conformal material to contact a first sidewall, asecond sidewall, and a bottom wall of each of a plurality of trenchescomprising the at least one trench; forming a circular opening in eachof the plurality of trenches over a contact of the plurality of contactsby etching a portion of the conformal material; and depositing, into thecircular opening, a chalcogenide material that contacts surfaces of thefirst sidewall, the second sidewall, and the bottom wall in each of theplurality of trenches, the chalcogenide material configured to storeinformation.
 22. The method of claim 21, further comprising: forming aplurality of pillars over the plurality of contacts in a hexagonalpattern; and coupling the plurality of pillars with a plurality ofselectors positioned in at least at one of a top and a bottom of anapparatus formed using the method of claim 21.